I was just wondering about this same thing (different emulator though).  I'll give it a try.

Ok, thanks for your advices guys. I've finally found the place where Gambatte stores the .sav files on OSX, if it can help anyone in the future :

users/yourusername/.config/gambatte/saves

You can find the folder in application support I think.

You know, it's funny you posted this because I experimented with something similar recently and I about sh*t when it actually worked. What cartridge are you using. I have the EMS64 here. Now then, I have a Windows Phone and have been playing  with the VBA8 emulator. My device is higher end so that may be part of it but I have to say it performs flawlessly. Anyway, I took a test .sav file from that and tried flashing it to my cart with the software that comes along with the cartridge. I made sure to use the very same LSDJ rom that is on my cartridge for the sake of keeping things kosher. I simply copied the sav, I had to rename it to Records.sav and flash that file to the cartridge. When I first booted up on my DMG, I got the corrupted Nintendo logo and thought it simply failed, no big deal. I rebooted a couple times and then it fired right up and the LSDJ sav loaded exactly with what was left from my phone.

Long story short, it worked! The whole reason I wanted to try this is because my phone is always with me, my DMG is not, so I could mess with a song on break at work for example and be able to keep any on the go work, yet still be able to playback and record from the real hardware at my convenience.

What I do not know is if the .sav from all Gameboy emulators are equal. In the case of VBA8, it works out for cartridge use just fine. I don't know a thing about Gambatte, but in all honesty you really don't have alot to lose. Good luck.

*Edit:
I also should mention that Johan's extractor worked there as well. The .sav from the emulator allowed me to extract the lsdsng's. Super cool.

I really love this emulator.
But I have never try to transfer the data ( save file )  from the emulator to the real hardware.
I know it put a savefile somewhere, but i don't know if it will work...

Hello everyone,

I finally received my LSDJ cartridge and started making music on it.
But before that, I've been working on the Gambatte emulator and I'd like to use the tracks I've composed on it... Do you know, by any chance, how to get a .sav file from this emulator ?

Thanks a lot in advance !